Memory devices having a three-dimensional structure have been proposed, in which a memory hole is formed in a stacked body including a plurality of electrode layers that function as control gates in memory cells and are stacked with a plurality of insulating layers each provided between the electrode layers, and a silicon body serving as a channel is provided on the side wall of the memory hole via a charge storage film.
In the stacked body including the plurality of electrode layers and the plurality of insulating layer in such a three-dimensional memory device, the memory hole is formed by, for example, a reactive ion etching (RIE) method. A memory film including the charge storage film is formed on the inner wall of the memory hole, and a channel body is formed inside the memory film. In a structure in which, for example, a source layer is provided below the stacked body, it has been proposed to remove the memory film formed on the bottom portion of the memory hole by etching for connecting the lower end of the channel body with the source layer. In this case, the memory film formed on the side wall of the memory hole is also affected by etching in some cases.